Figure 1. Tree with ripe fruits. Photo by J. Stevens, African Plants – A Photo Guide.
Axonomy and Nomenclature
Synonyms.Phialodiscus unijugatus (Baker) Radlk.
Vernacular / common names. Triangle tops tree (English); mkivule, mwakamwatu (Swahili); mpwakapwaka (Digo); muikoni (Kikuyu); shiarambatsa (Luhya); achak, bilo, ochol, ochond achak (Luo); muthiama (Meru); mubo, mubonyeni (Pokomo).
Plant Description
Life form. Tree.
Plant. Evergreen, dioecious, 6–9(–30) m tall, crown dense, rounded (Figure 1), bark smooth, but often with horizontal ridges and warts, grey to dark green; young twigs finely orange brown hairy, becoming smooth.
Leaves. Reddish when young, drying bright green or brownish; alternate, compound with up to 5 pairs of leaflets which are opposite, elliptic to oblong, 6–22 x 1.5–8 cm, upper pair largest, apex tapering, margin often wavy.
Flowers. Inflorescences in axils of current leaves, 5–10 cm long, petals c. 1.5 mm, flowers singly inserted in cymose groups, whitish or yellowish, sweet-scented [3].
Fruits and Seeds
Fruits (Figure 2) are reddish triangular capsules 2–3 x 2.5–3 cm, pointed at apex, usually 3-seeded; pink endocarp with yellow margins. Seeds (Figure 2) are ovoid, 1–2 cm long, glossy dark brown to black, with a bright yellow cup-shaped aril <1 cm long at the base [3].
Flowering and fruiting. In Kenya, the flowering period extends from April to June; fruits mature in October and November.
Distribution
Native to tropical Africa, from Guinea Bissau and Democratic Republic of Congo east to Ethiopia and Kenya, and south to Angola, Zimbabwe, Mozambique and extending into the subtropics in South Africa [3].
Habitat
Moist evergreen forest, semi-deciduous forest, dry areas of riverine forest, and in wooded grassland, sometimes persisting in cultivated areas [3]. Grown in central and western parts of Kenya.
Uses
In traditional medicine, an infusion of the roots, and ash from roasted stems, are used to treat fever [5]. Nausea and vomiting are treated with the fruit and medicinal ointments made from the seed oil. A fragrant cosmetic lotion has been made from soaking the pleasantly scented flowers in water. The leaves are cooked and eaten as a vegetable [6]. The wood is used for light construction, furniture, agricultural implements and carving, firewood and charcoal production. The flowers provide nectar and pollen for honey bees. Blighia unijugata is often planted as a shade tree in villages and in coffee plantations [9].
Known Hazards and Safety
No known hazards.
Conservation Status
Assessed as Least Concern (LC) in South Africa according to IUCN Red List criteria [10], and as Lower Risk-Near Threatened (LR-nt) in Zambia [2] and Zimbabwe [7], but has yet to be assessed in Kenya and to have its status confirmed in the IUCN Red List [4].
Seed Conservation
Harvesting. Mature red fruits are collected from the crown by hand-picking from low branches, or by spreading a net or canvas on the ground and then climbing the tree and shaking the branches to dislodge the fruits.
Figure 2 – External views of fruits, showing the reddish triangular three-seeded capsules and the seeds with yellow arils. Photo by J. Stevens, African Plants – A Photo Guide.
Processing and handling. Fruits are dried in the sun and then threshed lightly to minimise damage to the seeds. Alternatively, small amounts of seeds can be extracted by hand. Seeds can be cleaned by hand-sorting and detaching the yellow arils from the seeds.
Storage and viability. Seeds are orthodox [11] and after appropriate drying can therefore be stored at sub-zero temperatures for long-term conservation or in airtight containers in a cool dry place for short- to medium-term storage.
Propagation
Seeds. Dormancy and pre-treatments: Seeds of this species are reported to be non-dormant [1]. No pretreatments are required [8]. Germination, sowing and planting: No information is available on optimum incubation temperature or on light requirements for germination under laboratory controlled conditions. Further studies are needed to characterise seed germination fully. However, the seeds germinate readily without any pre-treatments, so this species can be propagated by seed in the nursery [8].
Vegetative Propagation. Stem cuttings and wildings can be used [8], the former root readily in sand [6]. This species grows rapidly and can be managed by coppicing and pollarding [8].
Trade
The wood is used locally and occasionally traded on the international market [9].
More from Wild Plants for a Sustainable Future:
Cover courtesy of The Royal Botanic Garden, Kew
Excerpted with permission from Wild Plants for a Sustainable Future: 110 Multipurpose Species, editedby Tiziana Ulian, Cesar Flores, Rafael Lira, Avhatakali Mamatsharaga, Kebadire K. Mogotsi, Patrick Muthika(t), Samodino Ngwako, Desterio O. Nyamongo, William Omondi, Abdoul K. Sanogo, Sidi Sanogo and Efisio Mattana. Published by the Royal Botanic Gardens, Kew, and distributed by University of Chicago Press, 2019. © The Board of Trustees of the Royal Botanic Gardens, Kew